rLP2086 is a recombinant 28-kDa lipoprotein that induces cross-reactive bacterial antibodies against a number of Neisseria meningitidis strains. Based on deduced amino acid sequence homology, two different subfamilies of rLP2086 were identified, A and B. These two subfamilies were used in the formulation of the MnB-rLP2086 vaccine samples containing 20, 60, 120, and 200 μg/mL each in 10 mM Histidine (pH 6.0), 150 mM NaCl, and 0.5 mg/mL aluminum with varying levels of Polysorbate 80 (PS-80). Polysorbate 80, also known, as TWEEN 80, is a nonionic surfactant and emulsifier derived from sorbitol, and is frequently used in pharmaceutical formulations as an emulsifier, solubilizer and stabilizer. The presence of Polysorbate 80 in the MnB rLP2086 immunogenic composition is believed to prevent aggregation during formulation, processing, filtration, filling and shipping, reduce filter membrane absorption, and reduce tubing absorption.